For centuries, wine has been sealed into bottles using natural cork. It is well known that natural cork can sometimes cause tainting of the wine. It is believed that the problem arises from production of 2,4,6-trichloranisole, caused when microorganisms in natural cork combined with chemical contaminants use in production processors to kill bacteria. The tainting can be severe, in that the wine is “corked” and is undrinkable. A less severe result is that the wine, while still drinkable, has been spoiled to a sufficient degree to change the wine and to leave an undesirable impression on the consumer, who may not be aware that the wine may have been subject to tainting.
It is estimated that approximately 10% of wine sealed with natural cork is adversely affected by cork taint. This represents a significant proportion of wine production and is most undesirable, both in terms of financial loss and also damage to the substantial investment made in promotion of wine brands.
At least one attempt has been made to overcome the problem, by substituting for cork a solid or foam polymeric material which is not vulnerable to drawbacks of natural cork. The drawback with these prior art “synthetic cork” stoppers arises from the difficulty of extraction. The “synthetic cork” stoppers are designed to be removed by a corkscrew. Once a corkscrew is inserted in the stopper, the circumference of the stopper may expand slightly to wedge it even more firmly in the bottle neck. As a result, much more force is require to remove such a “synthetic cork” stopper compared with a traditional cork stopper. Use of an auger-type corkscrew can cause some “synthetic cork” stoppers to crack. In most cases, it is necessary to use a particular type of lever corkscrew to remove a synthetic cork. It can be difficult to remove a “synthetic cork” stopper using auger-type corkscrews.